1. Field of the Invention
This invention relates to improvements in baby feeding bottles and particularly to an improvement in the manner in which the temperature of the liquid within the bottle is determined.
2. Description of the Prior Art
Based upon the fact that the temperature of mother's milk is approximately 37.degree. C., it has been recognized that milk/formula given to the unweaned should be at approximately this temperature. Liquid above or below this temperature may be rejected by the baby. If the liquid is accepted and is too hot, the baby's lips and mouth may be burned. If the liquid is too cold, it may bring a case of indigestion.
In the past, the most common method for determining the temperature of the liquid was simply the tactile feeling of the fingertip or the hand palm of a person having access to the feeding bottle. The determination was therefore often reliable as it simply depended upon the thermal feeling of a particular person having access to the feeding bottle and furthermore was not free from the influences of atmospheric or room temperature.
Some early temperature indicator means for baby feeding bottles involved the use of bimetallic coils. See, for example, U.S. Pat. No. 2,648,226 issued to P. R. Finch and U.S. Pat. No. 2,814,202 issued to R. D. Frans. Other temperature indicator means included the use of liquid bulb-type thermometers attached, by various methods, to the feeding bottle. See, for example, U.S. Pat. No. 2,091,605 issued to C. E. McCarty, U.S. Pat. No. 2,981,108 issued to A. K. Andersen et al, U.S. Pat. No. 2,319,101 issued to S. S. Anderson, U.S. Pat. No. 1,423,038 issued to V. I. Sims, U.S. Pat. No. 2,357,477 issued to R. T. Killman, U.S. Pat. No. 2,346,832 issued to L. Eisele, U.S. Pat. No. 2,094,520 issued to J. Benamy, U.S. Pat. No. 2,357,692 issued to T. F. Saffady and U.S. Pat. No. 3,682,344 issued to A. N. Lopez.
With respect to using liquid bulb-type thermometers there is the obvious breakage resulting from the fact that the bottle is being used by an infant and thus might be dropped or the bottle misused by the infant, thus possibly leading to cuts or poisoning. Furthermore, the predominant use of dishwashers and microwave ovens has effectively eliminated the ability to use liquid bulb-type thermometers in baby bottles.
U..S. Pat. No. 3,125,984, issued to H. Okuyama discloses a baby feeding bottle with a side wall having a plurality of spaced recesses. Each recess contains a strip of wax, the wax in each recess having a distinct melting temperature. Each recess also has a marker (e.g. a colored marker), located inwardly from its respective strip of wax. Thus, when the bottle is heated to different temperatures the wax melts to be transparent revealing the marker to the viewer and giving an indication of temperature. Disadvantages of the Okuyama device includes the expense in manufacturing as a result of the numerous parts. If convenient temperature readings are desired, several recesses and concomitant waxes and temperature markers would be required.
German Offenlegungsschrift 28 28 328 discloses a baby feeding bottle with a thermometer attached to either the inside or outside of the wall of the baby bottle. The temperature indicator may be different from a thermometer scale such as a color indicator. Disadvantages of the German device include the fact that by virtue of being a separate unit, the thermometer might be broken away, misplaced or damaged through normal misuse by the handler. These problems may be amplified if the thermometer is attached to the inner wall because the damaged bottle/thermometer may be used without even suspecting that it might be damaged. Using a damaged indicator unit could cause unintentional harm to the baby (liquid served in the bottle being too hot or too cold).
U.S. Pat. No. 4,156,365 issued to F. Heinmets et al entitled, "Temperature Indicator", discloses the use of a layer of thermochromic paint as an indicator of temperature on food-holding vessels. The paint is used for the specific temperature range of between 55.degree.-70.degree. C. to provide indications of the levels of temperature of which denaturation of the food, microbial, growth in the food and tissue injury to the consumer of food carried by the utensil would be likely and reverse the color changes when re-cooled.